ICD-10/A51.3

A51.3 ICD 2026 Code: Secondary syphilis of skin and mucous membranes

A51.3 is the authoritative medical code for Secondary syphilis of skin and mucous membranes. This classification is used in medical billing and clinical recording to specify the clinical criteria for secondary syphilis of skin and mucous membranes (ICD-10-CM A51.3), ensuring healthcare documentation aligns with 2026 federal coding standards.

Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.

Official Registry Overview & Definition

Secondary syphilis of skin and mucous membranes is a non-billable ICD-10-CM category code A51.3. A more specific billable subcode must be selected for claims submission. Excludes1 (not coded here): nonspecific and nongonococcal urethritis N34.1; Reiter's disease M02.3-. Excludes2 (not included here): human immunodeficiency virus HIV disease B20.

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for A51.3 in the official ICD-10-CM tabular list.

Excludes1 — Not Coded Here

Conditions that can never be reported with this code; the two are mutually exclusive.

  • nonspecific and nongonococcal urethritis N34.1
  • Reiter's disease M02.3-

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

  • human immunodeficiency virus HIV disease B20

Frequently Asked Questions (FAQ) & Clinical Guidance

Can A51.3 be billed directly?

No. A51.3 (Secondary syphilis of skin and mucous membranes) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

What can't be coded together with A51.3?

Per Excludes1 instructions, A51.3 must not be reported with: nonspecific and nongonococcal urethritis (N34.1); Reiter's disease (M02.3-).

Can A51.3 be reported alongside related conditions?

Per Excludes2 instructions, A51.3 and the following may both be reported when both are present: human immunodeficiency virus [HIV] disease (B20).

Codes in This Family (17)

Official ICD-10-CM classifications in the same code family as A51.3, with their registry titles.

  • A51 — Early syphilis
  • A51.0 — Primary genital syphilis
  • A51.1 — Primary anal syphilis
  • A51.2 — Primary syphilis of other sites
  • A51.31 — Condyloma latum
  • A51.32 — Syphilitic alopecia
  • A51.39 — Other secondary syphilis of skin
  • A51.4 — Other secondary syphilis
  • A51.41 — Secondary syphilitic meningitis
  • A51.42 — Secondary syphilitic female pelvic disease
  • A51.43 — Secondary syphilitic oculopathy
  • A51.44 — Secondary syphilitic nephritis
  • A51.45 — Secondary syphilitic hepatitis
  • A51.46 — Secondary syphilitic osteopathy
  • A51.49 — Other secondary syphilitic conditions
  • A51.5 — Early syphilis, latent
  • A51.9 — Early syphilis, unspecified

Related Codes & Numerical Sequence (Crawl Map)

Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures:

ICD Code A48.3 Toxic shock syndrome
ICD Code A49.3 Mycoplasma infection, unspecified site
ICD Code A50.3 Late congenital syphilitic oculopathy
ICD Code A52.3 Neurosyphilis, unspecified
ICD Code A54.3 Gonococcal infection of eye
ICD Code A56.3 Chlamydial infection of anus and rectum
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